The invention relates to an electric lighting lamp with double light source housed in a case, and containing:
a first bulb fitted in a first connecting base, PA1 a second bulb fitted in a second connecting base, and extending parallel to the first bulb, PA1 an electrical circuit equipped with a control device of two switches, which are connected respectively in series with said first and second bulbs, PA1 and a reflector and transparent screen element for transmission of the light beam emitted by each of said bulbs. PA1 a plate supporting the two connecting bases and the electrical circuit, said plate being made of insulating material and subdividing the inside of the case into a first front compartment receiving the bulbs, and a second rear compartment housing the electrical circuit, PA1 a switching bar of said control device having two actuating means staggered along a transverse axis in the second compartment, and cooperating alternatively with contact strips constituting the first and second switches to control total extinction or lighting of one of the light bulbs depending on whether the control device is in a break position or an active position, said switching bar being mounted with rotation in a bearing on one of the side faces of the case on the same side as the second fixed-focus bulb, PA1 and an adjustment knob separated from the control device and designed to move the first connecting base to focus the light beam emitted by the first bulb.
In a known lamp of the kind referred to, the device controlling the two switches is formed by a common selector switch having several successive selection positions, i.e. two Off positions, and two other On positions of the lighting. Moving from a break position to a make position to supply a bulb is achieved by a one-step rotation action of the selector switch, which is formed by a component having output studs electrically connected in the electrical supply circuit of the bulbs. Using a rotary selector switch of this kind implies multiple welds in the electrical circuit, which increases the assembly and manufacturing time of the lamp. In the case where the lamp is used as a head-mounted lamp, it is moreover particularly uneasy to identify with accuracy which of the two light bulbs is lit or extinguished when the lamp is fixed on the user's head.
In a mechanism described in the document U.S. Pat. No. 4,336,579, the same actuating device controls the two switches of the bulbs and the translation movement of the bulb with adjustable focus. A control of this kind requires a large angular movement.